Pilots of the solar plane that already set records flying without a drop of fuel are close to making their first attempt to fly the craft around the globe. They plan to do it in 25 flying days over a five-month period.

Solar Impulse 2, or SI-2 for short, arrived in Abu Dhabi in pieces. Built mainly of lightweight glass-reinforced plastic, it is now being re-assembled and prepared for its journey around the globe.

The concept was previously tested by its predecessor, Solar Impulse 1, in 2012 during a long flight from Europe to North Africa and in 2013, flying across the United States.

SI-2’s 72-meter-long wings are covered with more than 17,000 solar cells that can generate up to 52 kilowatts of power. The cells also charge batteries which run the plane's four electric motors at night.

The single-seat plane, which will take off from Abu Dhabi, will follow a course roughly along the equator, where the sun is strongest, touching down only every few days. Two pilots will take turns in the cockpit during those stops.

Project co-founder Bertrand Piccard, who is one of the pilots, says the flight will require a lot of endurance.

“It's very exciting for everybody, and we are also in the psychological preparation of the pilot and the team, because technology is o.k., but you need to cope now with very long duration flights: single pilot on board for five days and five nights. Lot of stress for everybody," said Piccard.

Co-founder and alternate pilot Andre Borschberg says although SI2 can fly on autopilot, they plan to rest or sleep only 20 minutes at a time.

“How many of these breaks we will be able to take per night, it's hard to say. We've trained in a simulator to have six to eight of them every 24 hours, which means about two hours of sleep every 24 hours, which is not a lot," said Borschberg.

Bertrand Piccard says the project's goal is to demonstrate the advantages of renewable energy sources and clean technologies.

“If an airplane can fly with no fuel around the world, can you imagine how this technology could be used everywhere?," he asked.

SI-2 is scheduled to take off in March and return to Abu Dhabi some time in July.